A new breed of mega-fund-raisers emerged in the final months of the presidential campaign, collectively hauling in millions of dollars from small numbers of people.

Critics say the practise gives some fund-raisers influence out of proportion with the intent of campaign-finance limits.

The campaign began with the rise of "bundlers," individuals who raise many small checks up to the $2,300 (€1786) cap imposed by a 2002 campaign-finance law to dilute the influence of big money. But it ended with mega-bundlers, a category documented by a study commissioned by The Wall Street Journal.

These are fund-raisers who have raised up to $70,000 apiece from individuals by channelling it through joint fund-raising committees, which spread the donations out lawfully. The trend helped fuel the most expensive presidential election in history.

"The purpose of the campaign-finance law is to limit not just donations but the influence of donors," said Alexander Cohen, a senior researcher at Public Citizen, a nonpartisan consumer advocacy group that conducted the study for the Journal. "So when you can drive up with a truckload of money to give to a candidate, it's hard to see how that's limiting influence."

The study documents for the first time the rise of mega-bundlers and the ease with which they get around normal donation limits. Many have raised hundreds of thousands of dollars single-handedly, often with just a flurry of emails and calls to business associates and relatives. Mikal Watts, a prominent product liability lawyer in Texas, raised $285,000 from 10 partners, including himself, for the joint fund-raising committee of Sen. Barack Obama, the Democratic presidential nominee.

"It didn't take any time at all," Watts said. He personally donated $28,500 to Sen. Obama's joint victory account, the Obama Victory Fund, and sent out emails that quickly raised the same amount from each of the other nine partners.

"This guy made fund raising the easiest thing in the world," Watts said. "I could have raised several million more if I could have gotten him back to Texas."

In the Republican camp, Scott Rothstein, a Florida lawyer, said he has raised $1.1m for Sen. John McCain and is in his "kitchen cabinet." Nothing was easier than soliciting money for the presidential candidate's joint fund-raising account, McCain-Palin Victory 2008, he said. At a fund-raising event at his Fort Lauderdale home this year, Rothstein and eight of his colleagues donated a total of $569,000 to the account.

"Of course it's an easier way of raising money," Rothstein said.

The 2002 campaign-finance law, championed by Sen. McCain, sought to reduce the influence of wealthy contributors by banning "soft money," or large financial donations to the Republican and Democratic political parties.

Now, critics say, mega-bundling is fresh evidence that the system still needs fixing, and are circulating proposals in Washington to revamp the government-financing system for presidential elections.

Advocates of finance change agree that the goal is to reduce the influence of big donors in politics. But some want to ban joint fund-raising accounts, while others want to lower the donation caps.

Congress faces a crowded agenda next year, but both Sen. McCain and Sen. Obama have championed campaign-finance revision in the past. Sen. McCain "would be open to bipartisan discussions of any proposals that improve the system," said his spokesman, Brian Rogers. Obama spokesman Tommy Vietor said that Sen. Obama would make fixing the broken campaign-finance system a priority in his administration.

Candidates in this election relied more heavily than ever on bundlers to raise the millions of dollars needed to compete in the presidential primaries. Norman Hsu, the famous bundler for Democrats, raised $850,000 for Sen. Hillary Clinton from hundreds of donors in increments of $2,300 or less and was indicted on charges of paying for the donations.

But once Sens. McCain and Obama turned to the general election, they created joint fund-raising committees, leveraging and accelerating the bundling process far beyond earlier efforts, in perfect compliance with the law.

Through October 15, the two presidential candidates had raised a total of $350m in their joint fund-raising accounts, about equally. In 2004, President George W. Bush and Democratic Sen. John Kerry raised a combined $51.4m for joint fund-raising accounts, up from a combined $5.2m in the 2000 presidential race.

The Public Citizen study found about 200 mega-bundlers. Public Citizen applied the mega-bundler category to those who were identified as bundlers by either presidential candidate and had solicited at least one contribution of $10,000 or more from a co-worker or member of their household for a candidate's joint fund-raising account.

Donors are allowed to give as much as $70,000 to the accounts. The accounts legally skirt fund-raising limits because the money doesn't go directly to candidates. Instead, it is split in legal-size chunks between national and state political parties that then spend it on behalf of the presidential candidates.

The study found Sen. McCain had 84 mega-bundlers. They include Hess chief executive John Hess, who was credited with $256,500 in contributions from himself and nine Hess employees. Hess declined to comment.

Henry Kravis, of Kohlberg, Kravis, Roberts, raised $322,000 from himself and 11 people in his office. Kravis declined to comment.

Sen. Obama and his supporters have touted a big infusion of small-dollar online donors as a sign that the spirit of campaign-finance reform was alive and well. But Sen. Obama had 119 mega-bundlers, according to the study.

Among them was John Arnold, an executive with Texas-based energy hedge fund Centaurus Energy, who raised $176,000 for Sen. Obama from himself and six people. He declined to comment.

Chris Pohlad rounded up $170,000 for Sen. Obama from himself and six people at PepsiAmericas. Pohlad, who left the company to joint the Obama campaign, declined to comment.

The 2008 presidential election campaign is on pace to have cost $1.6bn, twice as much as the 2004 race, according to a new study from the nonpartisan Center for Responsive Politics.

The Public Citizen study found that of the $488.3m total Sen. Obama raised for his general-election campaign and joint fund-raising account through Oct. 15, 15% came from donations of $25,000 or more to his joint committee. A total of 2,318 people made donations of $25,000 or more -- more than 10 times the normal legal limit -- for a total of $72.8m, according to the study.

About 20% of the $346.8m raised by Sen. McCain in his presidential account and joint fund-raising committee came from people who donated $25,000 or more. Sen. McCain received donations of at least $25,000 from 1,857 donors, the study found.

-- Write to Brody Mullins at brody.mullins@wsj.com and Ianthe Jeanne Dugan at ianthe.dugan@wsj.com